N-Butanol and ethyl acetate are commercially significant organic compounds having use in a wide variety of applications and which are produced in quantities exceeding 1 million tons per year. N-Butanol can be produced from several different reactions. The most common method for making n-butanol is hydroformylation. Propylene reacts with syngas over cobalt or rhodium catalysts at high pressures to produce an aldehyde (butyraldehyde), which is then hydrogenated over a nickel catalyst to give the alcohol. The drawbacks of such a process include the high energy costs associated with the generation of syngas, the use of a potentially non-renewable feedstocks (propylene and syngas are typically sourced from petroleum and natural gas, respectively), and the complexity of the process which requires multiple reactors and, typically, homogenous hydroformylation catalysts.
N-Butanol can also be produced from an aldol condensation reaction followed by hydrogenation. This method converts acetaldehyde to butanols, although the high toxicity and limited availability of acetaldehyde make such a process unattractive. Some processes, for example U.S. Pat. Nos. 1,992,480 and 8,071,823 both of which are incorporated herein by reference in their entirety, utilize a gas phase reaction to provide butanol.
Direct fermentation of sugars is another process for production of n-butanol. As a bioprocess this method suffers from long process times and large separation requirements in addition to the need for specialized microbes necessary to make butanol directly from sugars.